The present invention relates to a steering column unit which is adjustable in position for an automobile vehicle.
Some automobile vehicles have been provided for already several years with devices for adjusting the position of the steering wheel for the purpose of adapting the position of the latter to the morphology of the driver of the vehicle.
Thus the position of the steering wheel may be adjusted axially and/or angularly by the user.
Steering column units known in the art comprise a steering shaft one end of which carries a steering wheel while the other end is connected to the rest of the steering mechanism of the vehicle.
This steering shaft is mounted to be movable in rotation in a column body, for example by means of rotational guide means, and the body and/or the shaft are mounted to be angularly and/or axially movable between flanges of a structure for fixing the body to the rest of the automobile vehicle.
This fixing structure comprises at one of its ends means for locking in position the body and the shaft and therefore the steering wheel, the locking means being movable between a locking position and an unlocking position enabling the user to adjust the position of the steering wheel.
In the vicinity of the other end of the fixing structure, the latter includes a bearing for guiding the column body.
Different embodiments of these locking means have been proposed.
Thus, for example, the locking means may comprise a rod extending between the two flanges of the fixing structure, a first end of which rod bears against one of the flanges of the fixing structure while the second end is connected to locking elements whereby it is possible to move the flanges toward each other for locking the body, the shaft and the steering wheel in position.
Different embodiments of these locking elements have also been proposed.
Thus for example, these locking elements may be constituted by a screw and nut system, a toggle system, or a system employing an eccentric, connected to a shifting lever actuatable by the user.
Another embodiment of these locking elements is described in the document GB-A-2 113 164 in the name of the FORD MOTOR COMPANY LIMITED.
This document describes a column unit whose general arrangement is in the previously-described form and in which the locking elements comprise a stop member at the corresponding end of the rod, an intermediate bearing member in contact with the corresponding flange of a support structure and axially movable on the rod, and a shifting member disposed between the stop member and the intermediate bearing member, connected to a shifting lever and movable in rotation in a plane perpendicular to the rod between an active column-locking position and a withdrawn position for unlocking the column.
The confronting surfaces of the shifting member and the intermediate bearing member or the stop member, comprise, in respect of one, at least one projecting portion adapted to cooperate with a ramp of the other surface for the purpose of moving said two surfaces away from each other, and therefore the corresponding locking elements, so as to shift the flanges toward each other and lock the column in position upon the shifting of the actuating lever.
Various embodiments of the guide bearing for the column body in the fixing structure have also been developed.
However, these bearings generally comprise a bent portion of the structure extending in a plane roughly perpendicular to the flanges of the latter. This bent portion defines an opening in which the column body is engaged, a ring of an elastically yieldable material being interposed between the walls of said bent portion defining said opening and the column body, to enable the latter to move angularly and/or axially relative to the bent portion and therefore relative to the fixing structure.
It will be understood that this type of bearing has a number of drawbacks, in particular as to the maintenance of the column body in position without play in the fixing structure.